[Animal modeling] Establishment of ulcerative colitis model in mice by different administration methods of dextran sodium sulfate

  Objective To study the model of ulcerative colitis in mice after intragastric administration or free drinking of dextran sodium sulfate.

  Methods Thirty two male C57BL/6 mice were randomly divided into blank group, 3% DSS free drinking group, 5 g/kg and 6 g/kg DSS gavage groups, with 8 mice in each group, administered continuously for 7 days. The amount of drinking water, body weight, fecal properties and blood production of mice in each group were recorded every day, and the disease activity index (DAI) of mice was scored. On the 8th day, the mice were killed, the colon, thymus and spleen of the mice were separated, the thymus and spleen were weighed, and the immune organ index was calculated; The length of colon was measured, the pathological changes of colon were observed, and the histopathological score was made.

  Results The total DSS intake of mice in each treatment group exceeded 30 mg/g on the 7th day. Compared with the blank group, the DAI score of mice in the gavage group had no significant difference (P>0.05), while the DAI score of mice in the white drinking group increased significantly from the third day (P<0.01). Compared with the blank group, the colon of mice in each treatment group was significantly shortened (P<0.01), but="" the="" thymus="" index="" had="" no="" significant="" difference="" p="">0.05); The thymus index and colon atrophy of mice in the free drinking group were significantly lower than those in the gavage group (P<0.05). In terms of histopathological changes, the colon of mice in the 6 g/kg intragastric group had slight pathological changes; The pathological changes in colon of mice in the free drinking group were more significant, and the histopathological score was significantly higher than that in each dose group (P<0.01 or P<0.05).

  Conclusion When DSS was used to establish the model of ulcerative colitis in mice, the effect of free drinking was better than that of gavage.